Conventionally, an optical disk apparatus using CLV system differs in the rotational speed of optical disk depending on the position of an optical pickup in radial direction on the optical disk, so that it is needed to change the rotational speed of a spindle motor at seeking.
Therefore, a conventional optical disk apparatus rotates an optical disk based on the speed information obtained by reproducing data on recording tracks, stops servo control of a spindle motor and tracking control at seeking, thereafter, moves an optical pickup to the target position, and then resumes the tracking control and the servo control of the spindle motor.
The above method has been used because the signal that is a criterion of the rotational speed servo of optical disk is obtained from the reproduction signal of the optical disk. More specifically, since the optical pickup traverses helically the tracks of the optical disk at seeking, the accurate servo information can not be obtained.
Here, if the seeking distance becomes longer, it is necessary to significantly change the rotational speed of spindle motor. In the above method, there has been a problem that because the servo control of spindle motor starts after the optical pickup is moved, the time from the arrival of the command for seeking to the reading and writing of data after starting all servo becomes longer.